1. Field of the Invention
The present invention pertains to a reusable canning lid for use with canning food.
2. Description of the Prior Art
Metal lids canning lids are well-known to those who can food. These lids have an outer perimeter that is contoured to mate atop a typical glass canning jar. The bottom surface of the lid includes a gummy substance, or sealing compound, that provides the seal between the lid and the jar.
In use, food is placed in the jar and the lid is tightened on the top of the jar using a threaded ring, or screw band. The jar is then placed in a hot water bath or pressure cooker and the food is processed according to the requirements for that particular food item. During processing, the heated seal is softened, which allows pressurized air inside the jar to escape. The jar is then removed from the water bath once processing is complete. It is fairly common for the screw band to loosen up during processing, and so it is common practice to make sure that the screw band is tight upon removal from the heat. This helps ensure that the lid forms a seal with the jar, thereby creating a vacuum inside the jar when the contents have cooled. It is understood that this vacuum holds the lid tightly over jar and keeps the jar's contents sterile and preserved for a year or longer. Once the jar and its contents have cooled, the resulting vacuum is sufficient to hold the lid on the jar, and the screw band is preferably removed.
However, an inherent problem with metal lids is that they are not reusable. The gummy seal on the lids is only designed for a single use. Since many people who can food are fairly prolific, a need has been created for a reusable canning lid.
In reaction to that need, the inventor of the present invention previously invented a first-generation reusable canning lid. That canning lid is made from plastic and uses a ring gasket instead of the gummy seal found on a metal lid. The ring gasket is a separate piece from the plastic lid, but it is reusable along with the plastic lid. This product has been successful in the marketplace for many years.
However, this first-generation reusable canning lid must be used in a slightly different, yet specific, manner than traditional metal canning lids. The ring gasket on the reusable canning lid does not allow the heated jar to vent in the same way as the gummy seal on metal lids. Therefore, the screw band on the reusable canning lid must be tightened onto the jar (over the lid and ring gasket), and then slightly loosened in order to allow the ring gasket and the lid to vent. Once processing is completed, and while the jar is still hot, the screw band is then tightened securely to ensure a seal between the lid, the ring gasket, and the top of the jar. This method of use must be used for the first-generation reusable lid to ensure that the jar both properly vents during processing, and forms a seal during cooling.
That product was met with positive reviews from many customers who have reused that invention year after year, some customers having used their reusable canning lids for decades. However, there is an inherent learning curve involved with the process of initially tightening and then incrementally loosening the screw bands. The objective is to tighten the screw band to a specific torque range, but to achieve that torque range using nothing more than feel by the user. Moreover, users of the product vary in age, gender, health, and strength, and achieving the proper torque level for all users can be a challenge. Furthermore, the step of finger tightening the screw band and then slightly loosening the ring is very counterintuitive to those who are used to using traditional metal lids because those lids do not require the screw band to be loosened whatsoever.
This product was very well-received by those who had mastered the learning curve and were comfortable with using that product. However, product development continued for some time to address the issue of properly tightening the screw bands on the jars, including the potential use of placing indicator lines on the canning lid to help the user gauge how far to loosen the lid once it was tightened. Nonetheless, the problem of overcoming this learning curve was not discovered until recently.
As discussed hereinbelow, the inventor has addressed the issue of correctly tightening the screw band in a manner that is wholly unanticipated in light of the problem and previous attempted solution mentioned above.
The present invention, as is detailed hereinbelow, seeks to provide a canning lid that is fully reusable like its predecessor, but which is used by the customer in the same manner as a traditional metal lid and requires no additional training or skill to properly use the product.